果糖-赖氨酸模型体系美拉德产物不同级分对抑制香蕉酶促褐变相关性质的影响

非硫无毒的抗褐变抑制剂的筛选是目前的研究热点。前期研究显示果糖-赖氨酸模型体系美拉德反应产物对香蕉酶促褐变具有明显的抑制效果。本文研究了分级对该体系产物抑制香蕉酶促褐变相关性质的影响。首先通过超滤、透析等方法将美拉德产物分级为MW<3500 u、MW>5000 u及3500 u5000 u级分的螯合铜离子能力最好,MW<3500 u级分次之。MW<3500 u级分的DPPH?清除能力和抑制香蕉多酚氧化酶能力更佳,分别达46.13%、0.089 mg/mL（IC50）。三种级分对游离酶和酶-底物络合物的抑制常数分别为：KI=0.297 mmol/L,KIS=1.744 mmol/L（MW>5000 u）;KI=0.212 mmol/L,KIS=1.656 mmol/L（3500~5000 u）;KI=0.205 mmol/L,KIS=1.536 mmol/L（MW<3500 u）。说明MW<3500 u级分与游离酶及酶-底物络合物结合更紧密。综上,MW<3500 u的MRPs具有最优的抑制香蕉酶促褐变的能力。     

Sensory and Chemical Analysis of ‘Shackleton's’ Mackinlay Scotch Whisky

Three cases of Mackinlay's Rare Highland Malt whisky were excavated from the ice under Sir Ernest Shackleton's 1907 expedition base camp hut at Cape Royds in Antarctica in January 2010. The majority of the bottles were in a pristine state of preservation and three were returned to Scotland in January 2011 for the first sensory and organoleptic analysis of a Scotch malt whisky distilled in the late 1890s. Sensory analysis and the higher alcohol and maturation congener profiles describe a lightly peated malt whisky matured in American white oak sherry or wine casks. Analysis of process related compounds together with combined gas chromatography (GC) mass spectrometry and GC‐olfactometry analysis of fermentation related congeners show a distinctly ‘modern’ style of malt whisky. While Scotch malt whisky at the end of the 19th century was generally regarded as heavily peated and harsh in character, Charles Mackinlay & Co. Distillers were producing a malt whisky with an altogether more subtle character at their Glen Mhor distillery near Inverness. The sensory and chemical analysis of this unique whisky artefact significantly changes our understanding of the quality and character of Scotch malt whisky produced by our distilling forefathers.     

Reactive oxygen scavenging activity of matured whiskey and its active polyphenols

ABSTRACT:  The quality of whiskey is known to improve remarkably by its storage over many years. This process is commonly termed "maturing." In this process, polyphenols derived from lignin and tannin of the barrel have an important role in not only forming the matured flavor and taste but also contributing to the advance of clustering ethanol and water in whiskey. It is also likely that polyphenols generally possess reactive oxygen (RO) scavenging activity. The present study evaluated the RO scavenging activity (free-radical scavenging activity, H₂O₂ reduction activity under peroxidase coculture, and H₂O₂scavenging activity) of 24 single malt whiskeys with a maturation age of 10 to 30 y produced in Japanese, Scotch (Islay), or Scotch (Speyside and Highland) regions. Single malt whiskey not only showed RO scavenging activity but there was also a positive correlation between this activity and the maturation age of whiskey exceeding the difference resulting from the manufacturing region. A nonvolatile fraction derived from the barrel was responsible for RO scavenging activity. In particular, the contents of ellagic and gallic acids and lyoniresinol, the main polyphenolic compounds in whiskey, increased with maturation age. For the free-radical scavenging activity per molecule, each compound was 1.68 to 3.14 times that of trolox (a water-soluble vitamin E). The activities of ellagic acid, gallic acid, and lyoniresinol in the whiskey (Yamazaki 18) were equivalent to that of 80.3, 31.2, and 11.1 ppm trolox, respectively. Accordingly, the total activity of these 3 compounds accounted for about 20% of the activity of the whiskey (630.7 ppm trolox).     

不同酵母对威士忌品质的影响

以大麦芽为原料,选用3种不同酵母（ACBC-1、ACBC-2及ACBC-3）发酵制备威士忌。比较不同酵母的发酵性能、理化指标及出酒率,采用气相色谱（GC）法测定威士忌挥发性香气物质,通过气味活度值（OAV）确定关键香气化合物并进行主成分分析（PCA）,并对制备的酒样进行感官评价。结果表明,酵母ACBC-1发酵性能最好,其发酵液的理化指标良好（总酸3.73 g/L,残糖3.00 g/100 g,酒精度6.42%vol,pH 4.1）,出酒率最高（70.78 mL/kg）。3个酒样共检出24种风味物质,其中醇类化合物为主,占77%～98%;OAV＞1的酯类化合物种类最多（5种）,其中乙酸苯乙酯、乙酸异戊酯及乙酸苯乙酯是关键香气物质,对酒样的香气贡献最大。3种酵母制备威士忌酒样感官评分顺序ACBC-1（90分）＞ACBC-2（76分）＞ACBC-3（71分）。结果表明,酵母ACBC-1适合酿造威士忌。     

The influence of malt and wort processing on spirit character: the lost styles of Scotch malt whisky

Over the last 50 years there has been considerable analytical research on the malt parameters which govern the flavour and aroma, i.e. the ‘character’, of Scotch malt whisky. This has led to a standard format, the Flavour Wheel, to describe the attributes of any malt spirit and to relate them to a common group of malt parameters. What has not been well documented in the same period are the changes in malt processing technology which have led to a gradual but significant change in the concentrations of reference compounds used in the Flavour Wheel relating to sulphury, nutty/burnt/smoky, peaty and fruity/estery characters. This review covers the most significant of these changes, which have become common practice across the industry, and specifically demonstrates how different malting barley varieties, malt kilning and peating, wort recovery, yeast management, and wash still heating have all contributed to the loss of some styles of malt whisky. © 2019 The Institute of Brewing & Distilling     

The Impact of Copper in Different Parts of Malt Whisky Pot Stills on New Make Spirit Composition and Aroma

In Scotch malt whisky production, the use of copper for the construction of the pot stills for distillation is regarded as having an important effect on whisky aroma. During distillation in copper pot stills, the copper acts to reduce sulphury aromas in the resultant spirit by reducing the levels of sulphur compounds such as dimethyl trisulphide (DMTS). This work has shown that the copper is more effective in this role in some parts of the pot stills than others. This information can be used to help distillers maintain or, indeed, to alter new make spirit aroma. It was also noted that in addition to DMTS, other, as yet unidentified, compounds make a significant contribution to sulphury aromas, so future research efforts should focus on identifying such compounds.     

北五味子麦芽酵素的制备及其抗氧化活性

以超氧化物歧化酶（SOD）活力为评价指标,通过单因素试验以及正交试验,对植物乳杆菌（Lactobacillus plantarum）发酵的北五味子麦芽酵素的发酵工艺条件进行优化;并对该酵素产品的抗氧化活性进行了研究。结果表明,植物乳杆菌发酵制备北五味子麦芽酵素的最佳发酵工艺条件为北五味子∶麦芽=2∶1（g∶g）,发酵时间为3 d、接种量为1.5%、发酵温度为41 ℃。在此最佳工艺条件下,北五味子麦芽酵素SOD酶活力为3 464.80 U/mL。抗氧化活性结果表明,该酵素对超氧阴离子自由基清除能力、羟自由基清除能力、DPPH自由基清除能力和对ABTS+自由基清除能力分别达到了26.03%、97.25%、89.10%和0.613 7 mmol/L,表明该酵素具有较好的抗氧化活性。     

两种泥煤对威士忌品质的影响

目的 为丰富国内威士忌产品的种类。方法 以澳大利亚麦芽为主要原料,分别利用阿坝州泥煤和拉脱维亚泥煤烟熏麦芽制作麦芽汁,再用酿酒酵母酿造泥煤威士忌;并对比两种威士忌的感官特征、理化指标及香味成分。结果 阿坝州泥煤烟熏过的麦芽汁发酵后的出酒率(24.2±1.18%)显著高于(P＜0.05)拉脱维亚泥煤,感官品质也显著优于(P＜0.05)拉脱维亚泥煤威士忌,且水果香和花香突出。通过气相色谱与质谱联用技术(Gas chromatography-mass spectrometry,GC-MS)分析两种威士忌的香味成分,共检测到20种挥发性物质,包括5种醇、5种酸、6种酯及4种其他物质;阿坝州泥煤威士忌中乙酸乙酯和异戊醇占比显著高于(P＜0.05)拉脱维亚泥煤威士忌;拉脱维亚泥煤威士忌中酸类化合物较多,酒体欠协调。结论 综合分析得出阿坝州泥煤更适用于威士忌酿造;研究结果为国产泥煤的应用和威士忌产品个性化发展提供借鉴意义。     

The Evolution of Dextrins During the Mashing and Fermentation of All‐malt Whisky Production

The production of malt whisky involves the mashing of barley malt, followed by the fermentation of the resulting wort without further treatment. While this process has many parallels to the production of an all‐malt beer, one of the main differentiating steps during substrate preparation is the inclusion of a boiling step for the wort in the production of beer. Other than the destructive action of the boiling process on microorganisms, the boiling also destroys all malt enzyme activity. Since a typical whisky wash is not boiled it carries through a certain proportion of microbial activity associated with the malt, but more importantly it retains some enzyme activity that has been activated during the malting and mashing processes. The changes in sugars and dextrins during both mashing and fermentation of the resulting wash were investigated. Evidence of the continuous amylolytic activity during an unboiled, all‐malt wash fermentation is shown; while no ongoing amylolytic activity could be deduced during the fermentation of a boiled all‐malt wort. Furthermore, the data suggests that the amylolytic activity during mashing and fermentation are different with regards to α‐amylase action linked to its multiple‐attack action pattern as a function of substrate conformation, temperature, and effectiveness of potential hydrolytic events.     

威士忌麦芽新酒在Oloroso雪莉桶陈酿两年后挥发性风味成分的变化

为了对比麦芽新酒及采用Oloroso雪莉桶陈酿两年麦芽威士忌的差异，按照相关国标方法测定两种酒品质指标，并采用气相色谱-质谱联用（GC-MS）技术检测其挥发性风味成分。结果表明，陈酿酒的风味和口感均优于麦芽新酒，两种酒感官指标、理化指标及卫生指标均符合相关国家标准。两种酒共计检出105种挥发性风味化合物，其中麦芽新酒、陈酿酒分别共检出85种、86种，主要为醛类、酯类、醇类及酸类，醛类含量由4.44 mg/L增加至10.53 mg/L，酯类含量由257.34 mg/L增加至289.20 mg/L，醇类含量25.26 mg/L增加至54.96 mg/L，酸类含量85.18 mg/L增加至88.97 mg/L。陈酿麦芽新酒橡木桶类型和地理环境的差异导致其挥发性风味成分的变化，Oloroso雪莉桶陈酿麦芽新酒2年后呈现良好的品质及风味，但距离威士忌成品尚有差距，还需继续桶陈监测最终达到风味协调所需要的时间。     

The Survival of Limit Dextrinase during Fermentation in the Production of Scotch Whisky

Limit dextrinase, is an important enzyme in the hydrolysis of starch from cereals to fermentable sugars. Work is described which demonstrates the importance of this enzyme in the production of Scotch whisky. The study considers the occurrence, survival and action of limit dextrinase (total and free) during fermentation in malt and grain distilleries. The results of both laboratory and distillery studies revealed that limit dextrinase can survive the conditions encountered during mashing and is not only present in the fermenter but its activity can increase during fermentation. This observation has important implications for the production of Scotch whisky, since the fermentation substrate (wash) is not boiled, the enzyme is therefore available to degrade dextrins into fermentable sugars, and can potentially increase the yield of alcohol.     

AMINO ACID ANALYSIS OF BEER POLYPEPTIDES

The principles of amino acid analysis of proteins and polypeptides are reviewed. Analysis of the amino acid composition of dialysed beer material prepared from a wide variety of commercial and pilot brewery beers showed that the principal amino acids comprised glutamic acid/glutamine, proline, glycine and aspartic acid/asparagine. The results from the analysis of a series of pilot brewery beers brewed under standardised conditions showed that the composition of the grist may influence the amino acid composition of beer polypeptide fractions. Dialysed beer material prepared from beer brewed from grists containing torrified wheat, wheat flour and malted wheat contained greater proportions of glutamic acid/glutamine compared to material prepared from all malt beers. Further fractionation and analysis of dialysed beer material prepared from pilot brewery beers suggested that fractions MW>60000 contained polypeptide material derived from yeast mannan-protein. In addition fractions MW>60000 prepared from beer brewed from grists containing torrified wheat, wheat flour or all malted wheat may contain high molecular weight polypeptide material derived from wheat proteins. The results from the analysis of fraction MW 40,000–60000 prepared from beers brewed from grists containing all malt, 80% malt and 20% torrified wheat and 50% malt and 50% malted wheat are consistent with the presence of polypeptide material derived from cereal albumins and globulins whereas fractions MW 40,000–60000 prepared from beers brewed from 80% malt and 20% wheat flour and 100% malted wheat may contain polypeptide material derived from wheat prolamins and glutelins. The amino acid composition of fraction MW 20,000–40,000 from all pilot brewery beers investigated is consistent with the presence of polypeptide material derived from cereal prolamins and glutelins. The amino acid composition of beer polypeptide fractions may be used to detect the use of wheat adjuncts in beer brewing.     

The (1–3, 1–4)‐β‐Glucanases in Malting Barley: Enzyme Survival and Genetic and Environmental Effects

Eighteen barley genotypes used in Brazilian malting barley breeding programs were characterized in relation to (1–3, 1–4)‐β‐glucanase activity in green and kilned malt. They were tested to determine the loss of enzyme activity during kilning in the malting process and the environmental effects on enzyme activity were measured. The genotypes analyzed showed great variation regarding the enzyme activity in both kinds of malt, in a range from 531.94 to 934.31 U/kg in green malt, and from 187.02 to 518.40 U/kg in dry malt. The mean enzyme activity loss during kilning was close to 60%, very similar to the results obtained in other studies. The loss among genotypes varied from 8.04% to 71.54%. The enzyme activity varied significantly under the different environments tested, showing existence of environmental effects on the genotypes analyzed. Embrapa 127 was the genotype that exhibited the highest enzyme activity in finished malt although it had shown a low activity in green malt, reflecting a negligible loss of activity during kilning. The data indicate promising results to malting barley breeding due to the wide variability exhibited by genotypes as to enzyme activity and levels of isoenzyme with high thermostability.     

An antioxidant protein in Curcuma comosa Roxb. Rhizomes

Curcuma comosa Roxb. is an indigenous Thai herb which is usually used as a food ingredient but it is also used in traditional folk medicine for the treatment of uterine inflammation. The crude protein extract from the rhizomes of this plant was found to possess free radical scavenging capacity, as detected by the DPPH assay. This antioxidant activity was purified by DEAE anion exchange chromatography to a fraction (called IE-1) that was comprised of a single main protein band of ∼18 kDa (UB-DEAE), as determined by SDS–PAGE resolution with Coomassie blue staining, and had a specific activity of 193.8 U/mg. In-gel trypsin digestion of the SDS–PAGE resolved UB-DEAE band followed by liquid chromatography–tandem mass spectrometry produced three reliably sequenced peptides, which all were found to very likely be fragments of a superoxide dismutase homologue (SOD, EC 1.15.1.1), an antioxidant enzyme that has been found in several plants. In support of this notion, the IE-1 fraction was found to yield positive results with the riboflavin–nitroblue tetrazolium (NBT) assay, a standard test for SOD-like activity. Together, these data then support the existence of an SOD homologue antioxidant protein in the rhizomes of C. comosa as a contributing agent to the total observed antioxidant activity.     

Acids in chicory roots and malt

A determination method for non-volatile acids in roasted chicory roots and roasted barley malt is described. The clean-up was accomplished using preparative gel electrophoresis followed by gas chromatography (GC)/mass spectrometry of the methoximes (ketonic acids) or trimethylsilyl derivatives (all acids). Using these methods, 64 non-volatile acids have been identified in chicory (among those 48 for the first time). In barley malt 60 acids could be detected (47 for the first time). Ten commercially unavailable substances have been synthesized. Most of the acids have been quantified using the same clean-up and GC/selected ion monitoring or GC/flame ionisation detection (FID). The recoveries range from 41 to 105% (average 79%), the detection limits from 1 to 72μg/kg being somewhat lower for the FID and considerably lower for malt, and the relative standard deviations from 1 to 10% for the main acids, from 2 to 89% for the minor acids and from 8 to 133% for the trace acids. In addition formic and acetic acids were determined by isotachophoresis.     

FLAVOUR AND HAZE STABILITY DIFFERENCES DUE TO HOP AND MALT TANNINS IN ALL-MALT PILSNER BEERS BREWED WITH PROANTHOCYANIDIN-FREE AND WITH REGULAR MALT

All-malt Pilsner beers were brewed with and without hop and malt proanthocyanidins by using regular malt and whole leaf hops as well as proanthocyanidin-free malt and n-hexane tannin-free hop extract. The different beers were analysed chemically and presented to an expert panel to detect possible differences in bitterness and astringency. The impact of proanthocyanidins on the formation of haze was demonstrated clearly. No differences between the beers were found in triangular tests although their levels of total polyphenolics and anthocyanogens differed by about 225 and 85 mg/litre. Statistical analysis of the paired comparison tests showed only very slight differences between beers with or without hop and malt proanthocyanidins. Thus, proanthocyanidin-free beer was considered less than slightly more bitter and astringent than regular beer and there was a very slight preference for the latter.     

Potential of Hull‐less Barley Malt for Use in Malt and Grain Whisky Production

Hull‐less (or husk‐less) barley is possibly one of the most important developments in barley in recent years. This study looked at the potential of hull‐less barley for use by the Scotch whisky industry. By modifying the malting conditions for hull‐less barley, it was possible to provide good alcohol yield as well as significant improvements in processing characteristics. The biochemistry controlling the germination of hull‐less barley was consistent with established knowledge about ‘normal’ hulled barley except that care is needed to ensure the consistency of feedstock, particularly since hull‐less barley may be prone to embryo damage during harvesting in the field. Our results indicated that the new batches of hull‐less barley studied, produced malt that gave much improved mash filtration rates in comparison with previous batches of material. These experiments demonstrated that by changing the malting conditions, to give a much shorter steeping cycle (8 h), it is possible to reduce water usage substantially in the malting industry, since only one ‘wet’ cycle was used, and also reduce germination times since optimum alcohol yield was achieved on day 4 germination rather than day 5 for conventional husked barley. This could save costs in terms of water, energy and time for the malting industry. The study also confirmed the potential of hull‐less barley for providing significant benefits for Scotch whisky distillers, both in terms of higher alcohol yields, and increased throughput, by showing that it is possible to overcome some of the filtration issues that have been previously associated with hull‐less barley. This study indicated that the new material was better suited than previous batches to both malt and grain distilling, both in terms of enzyme development and potential distillery performance, and further showed that viscosity problems associated with grain distillery co‐products can be significantly reduced when using hull‐less barley malt in the grain distillery. These would be substantial potential benefits for the Scotch whisky distilling industry.     

Composite malt with dark-purple rice malt improves the phenolic profile and antioxidant activity of malt extract

This research presents a modification of bioactive compounds of malt extract produced from Riceberry rice malt (RRM)–barley malt composite for malt-based beverage. Malt extract was produced by varying RRM at 20% w/w, 40% w/w, 60% w/w, 80% w/w, and 100% w/w and were analysed for total polyphenol content (TPC), phenolic acids constituent, and antioxidant activity. The 100% RRM extract was rich in TPC relative to 100% w/w barley malt extract. The composite malt extract containing 40% w/w–80% w/w RRM had enough TPC in the filtered malt extract (236–524 mg L⁻¹) and boiled hopped malt extract (216–485 mg L⁻¹) and were directly proportional to the antioxidant activity in the extract. Barley malt fraction in the malt extracts had a positive response on ferulic acid and sinapic acid, whereas RRM inclusion in malt extract increased p-coumaric acid, vanillic acid, rutin, and methyl coumarate concentration. Therefore, the cereal malt composite could provide strong oxidative stability to the malt extract and derived products.     

Effect of the Variety of Barley and Pearling Rate on the Quality of Shochu Koji

In liquor production, barley koji is used a source of saccharification enzymes, nutrition for yeast multiplication, and to impart flavor to the shochu product. Its role is analogous to that of malt in beer and whisky production. In this report, the influence of barley variety and pearling rate on barley koji characteristics is shown. Four Australian varieties (Stirling, Schooner, Arapiles, Grimmett) and one Japanese variety (Nishinohoshi) were evaluated. Significant differences were observed among barley varieties and pearling rate with respect to the amount of koji mycelia produced, enzyme activity and the amino acid composition of the barley koji.